The reasons why in my opinion so many poly relationship fail can be summed up by "too many cooks spoil the soup."
Too many have people meddling in relationships that are not their own. My husband has no say what so ever in my relationship with Murf. Just like Murf has no say in what goes on between Butch and I.
40 yo straight female
Married in the eyes of the government to Butch since 2001...
Murf my monogamous second husband has been with me since May of 2012.
In a V relationship with an average 60/40 split of time. Only due to Murf's and Butch's crappy work schedules.